In Patent Document 1, a turbo-supercharger control apparatus for an internal combustion engine equipped with a first and a second turbo-supercharger is disclosed. The compressors of the first and second turbo-superchargers are arranged in parallel in an intake passage, and similarly, the turbines of the first and second turbo-superchargers are arranged in parallel in an exhaust passage. The first and second turbo-superchargers are each equipped with a variable nozzle as a variable supercharging device. An intake switching valve for regulating the flow rate of air that passes through the compressor of the second turbo-supercharger is arranged in the intake passage. An exhaust switching valve for regulating the flow rate of exhaust gas that flows into the turbine of the second turbo-supercharger is arranged in the exhaust passage. Further, the exhaust passage is equipped with an exhaust bypass passage that bypasses the exhaust switching valve at a position that is upstream of the turbine of the second turbo-supercharger, and an exhaust bypass valve that opens and closes the exhaust bypass passage.
According to the above described turbo-supercharger control apparatus, in a mode that performs supercharging using both the first and second turbo-supercharger, the opening degree of the variable nozzle of the first turbo-supercharger is controlled so that an air amount ratio between the two turbo-superchargers becomes a predetermined target air amount ratio. Further, when switching from a mode that uses only the first turbo-supercharger to the aforementioned mode that uses both of the turbo-superchargers, the following operation is executed to suppress torque shock. That is, when the intake switching valve, the exhaust switching valve and the exhaust bypass valve are each controlled from a closed state to an open state to perform the aforementioned mode switching, these three valves are opened in the order of exhaust bypass valve, exhaust switching valve and intake switching valve.
Following is a list of patent documents which may be related to the present disclosure
[Patent Document 1]
JP 2008-190412 A
[Patent Document 2]
JP 2004-278430 A
[Patent Document 3]
JP 2008-045524 A
[Patent Document 4]
JP 09-195781 A
[Patent Document 5]
JP 06-207522 A
An internal combustion engine may be equipped with a first supercharger (turbo-supercharger) having a first compressor that is driven by exhaust gas, and a second supercharger (for example, an electric supercharger) having a second compressor that is driven by a power other than exhaust gas, in which the first compressor and the second compressor are arranged in parallel in an intake passage. After a request is made to increase the engine torque in an internal combustion engine having such a configuration, the torque response can be improved by utilizing supercharging by the second compressor to assist supercharging by the first compressor. Therefore, where a torque request is made, it is desirable to promptly start supercharging by the second compressor. However, if supercharging by the second compressor is started in a state in which the power of the first compressor is small at a time of a torque request, a surge may occur in the first compressor. Once a surge occurs in the first compressor, the first compressor may remain stuck in the surge state while the second compressor is operating. Further, because the first compressor may not increase the supercharging pressure while a surge is occurring, the first compressor may not secure a high torque response. Therefore, it may be desired raise the power of the first compressor before starting supercharging by the second compressor. In order to raise the power of the first compressor in this way, it may be desired to provide a predetermined amount of energy to the first compressor during a period from receipt of a torque request to a start of supercharging by the second compressor. Accordingly, in order to raise the power of the first compressor before starting supercharging by the second compressor, it may be desired to appropriately adjust an opening degree of an exhaust energy adjustment device and the start timing of supercharging by the second compressor.